Fuse mechanism for projectiles.



E. GATHMANN.

FUSE MECHANISM FOR PROJECTILES.

APPLICATION FILED JUNEZO. 1917.

1,292,395. Patented Jan. 21,1919.

' 2 SHEET$SHEET 1- A Gumm E. GATHMANN.

FUSE- MECHANISM FOR PROJECTILES.

I .Patented Jan. 21, 1919.

2 SHEETS SHEET 2.

llllllIIllYl/IL- wmmw UNITED STAT ES PA TENT OFFICE.

EMIL GATHMANN, OF BALTIMORE, MARYLAND.

FUSE MECHANISM FOR PROJ'ECTILES.

To all whom it may concern:

Be it known that I, EMIL GATHMeNN, a citizen of'the United States, residmg' at Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Fuse Mechanism for Projectiles; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accounpanying drawings, forming part of this specification.

In the fuse mechanism commonly employed in connection with projectiles designed to be -fragmented by an internal bursting charge, provision is made whereby a time train or fuse will be 1i hted during the initial movement of the projectile under the influence of the propelling charge, and the length of the fuse or train determines the period of time intervening between the discharge of the projectile and the time when the bursting charge is ignited. In addition the fuse mechanism also embodies a percussion igniting device or devices which will come into actionfor igniting the bursting charge when the flight of the projectile is interrupted or retarded as by contact with its target. Ordinarily, the time train is ignited while the projectile is well within the bore of the gun, the most common arrangement being a percussion primer or detonator which is fired by an inertia memher which tends to remain stationary, while the projectile and 'body of the fuse move forwardly with relation thereto, with the result that the primer or detonator is exploded during the acceleration movement of the projectile. This arrangement has developed irregularities in action and produced conditions which under some circumstances have caused premature explosion. The irregularity in action is thought to be largely due to the fact that the projectile in moving forwardly in the bore of the gun necessarily compresses and expels the volume of. air in the gun bore and the longer the gun, the greater the compression and volume of air necessarily'expelled. The time or fuse train burns more rapidly under increased air ressure, and inasmuch as the air pressure as' directaccess to the time train there may be as much as two or three seconds difierence in the rate of burning,

Specification of Letters Patent.

Patented Jan. 21, 1919.

Application filed June 20, 1917. Serial No. 175,918.

although the time interval may be as little as -3 of a second. Roughly speaking, each inch of barometer pressure or each half pound pressure of the air increases the rate of burning of a second on a 21-second burning fuse. As it is possible that the air pressure surrounding the fuse, while in the 'bore of the gun, may be as high as 100 pounds per square inch, it will be readily appreciated that the error or unequal burning will be a marked factor for which empirical adjustment must be made. Tests indicate that the error found to exist when a overcome the errors pointed out and to provide a detonator mechanism which will ignite the time train at a time when it is not subjected to the air pressure within the bore of -the gun, but, on the contrary, when it has actually begun its flight from the muzzle of the gun. In the preferred arrangement, provision is made whereby the detonator will be exploded immediately after the projectile has received its maximum acceleration or has acquired its greatest velocity, this usually occurring at from 10 to 30 feet from the muzzle of the gun. The firing of the detonator at this time is accomplished by what might 'be termed the rebound or sprlng actuated action of a detonator firing member which has been initially displaced durmg the acceleration period of the proectile, and which is moved in a reverse direction when acceleration decreases or deceleration begins. Referring to the accompanying drawmgs,

Fi re 1 is a section in a plane longitud1na t0 the axis of a fuse mechanism embodylng the present invention with the parts in normal position.

Flg. 2 1s a sectional view substantially in the plane indicated by the line 22, Fig. 1.

Fig. 3 is a sectional view of the end portion of the mechanism shown in Fig. 1, with the parts in the position assumed by them during the acceleration period of the projectile.

Fig. 4 is a view corresponding to Fig. 3,

' by a screw-thread connection in the nose portion of the projectile or in a housing, which housing is 1n turn secured in the nose portion of the projectile. A forwardly extending stem-like portion A of the fuse body A serves as the support for one or more rings or annular bodies B, B, and a cap or nut O which is threaded on the end of the stem and retains the rings in position. The cap 7 C and stem itself are formed with an internal chamber preferably of cylindrical formation, for the reception of the firing mechanism of the detonator to be. presently described. The rings B, B are provided with internal passages in which the time train or fuse composition D, D is located,

and one of the rings is usually made adjustable about the stem for setting the length of the time train, whereby the period during which the train will burn may be set at any point from zero to the full length of the train and time for which it is designed. This construction is well known and 1s preferably in. accord with so-called .standard practice. To permit fumes to escape during the combustion of the time train, the fuse mechanism is provided with vent openings E usually located in the cap piece C and having their external ports beneath an overhanging part or flange '0 formed as a part of said cap.

In the base of the body A there may be located a percussion detonator P which may be of any approved type adapted to in variably ignite-the charge upon impact of the projectile against its target, but which percussion mechanism forms no part of the present invention and may therefore be of any preferred type or omitted.

he time train igniting or detonati mechanism of the present invention, whi di may be located at any point in the fuse body, or for that-matter, inthe projectile itself, is conveniently and preferably mounted in the chamber formed in the forward end .of the body stem and cap C. It embodies a movable inertia member normall supported by a spring G in suchwise that it occupies a .forward position in the chamber but during the acceleration of the pro ectile, its

'weightor inertia will cause it to move to the rearend .of the chamber and compress the spring, which condition is maintained until acceleration is practically at its maximum or even until deceleration begins; whereupon the spring will assert itself and drive the member F forwardly in the chamber with relation to the body of the fuse and mechanismis provided whereby, upon such for-.

ward movement, the detonator will be fired so as to ignite the fuse or time train.

The simple mechanism illustrated embodies a spring retainer H having deformable or yielding arms h the ends of which are turned to engage an abutment preferably formed by a locking ring I,, whereby the normal position of the body F is maintained with the detonator K removed a short distance from the firing pin is. In the preferred construction, the locking ring I, or abutment for the engagement of the retaining spring is. also movable longitudinally in the chamber andwill, because of its inertia during the acceleration period of the projectile advance at less speed than or move rear- Wardly with relation to the projectile until it overcomes the resistance of the locking arms or retainers k and with the inertia member F assumes substantially the position shown in Fig. 3, where, in effect, it becomes a part of the inertia member.

Conveniently, the firing pin is is formed on the cap C and the detonator K is carried in the spring actuated inertia member F, in which position it may be confined by a tubular compression member M through which 'the flash from the detonator Kpasses back into the chamber and through a lateral opening N for igniting the time train.

In operation and assuming that the parts are inthe position shown in Fig. 1, when the propelling charge in the gun is exploded and the projectile is acquiring its velocity,

the parts willmove from the position shown in Fig. 1 to the position shown in Fig. 3; that is to say, the inertia member F will move backwardly, thereby compressing the spring G, and the locking ring I will deform or release the retaining arms 7;. and add its weight to that of the inertia member for insuring such action. When the projectile has acquired its velocity, and the effect of inertia on the inertia. member F and locking ring has been overcome through the latter acquiring the velocity of the projectile, the parts will rebound or advance with a very considerable velocity, bringing the parts into the position shown in Fig. 4, where the firing pin contacts with, and fires the detonator K. The flash from the detonator K ignites the time train and thereafter the action in all resglects corresponds to the action of the usual se mechanism. Y

Obviously, the arrangement of 'the inertia .member to fire the detonator on the rebound or spring actuated movement is subjected to considerable variation and various known memes or preferred arrangements of locking mechanism to be released either during the acceleration period or thereafter may be provided in connection with the inertia member without departing from the underlying invention embodied in the simple form adopted for illustration.

The spring herein designated as the actuating spring may be either a coil compression spring, as illustrated or any body sufliciently elastic to cause the rebound of the inertia member. The air cushion or the pressure of the air in rear of the inertia member produces the desired result, but more certain and effective results are secured where a spring is employed to act in conjunction with any other forces to produce the desired relative forward movement of the inertia member.

What is claimed is:

1. A fuse for projectiles, embodying a rearwardly movable inertia member, a normally expanded spring put under tension by the rearward movement of the inertia member for movin the member forwardly when the said meml er has acquired its veloc ity, a detonator, and means whereby the detonator will be fired by the rebound forward movement of the said member under the influence of its spring.

2. A fuse for projectiles embodying a time train, a rearwardly movable inertia member, an actuating spring put under tension by the rearward movement of the inertia member while acquiring the velocity of the projectile, a detonator, and means whereby the detonator will be fired by the rebound or forward movement of the inertia member, under the influence of its actuating spring to ignite the time train after the projectile leaves the gun.

3. A fuse for projectiles embodying an inertia member movable rearwardly longitudinally of the projectile, a normally expanded actuating spring put under tension thereby while the inertia member is acquiring the velocity of the projectile, a detonator, means for firing the detonator when the inertia member advances under the influence of its actuating spring, and locking means for normally holding the detonator firing means out of operative relation and adapted to be released when movement of the inertia member takes place.

4 A' fuse for projectiles embodying a time train, an inertia member movable rearwardly longitudinally of the projectile, a normally expanded actuating spring put under tension by the rearward movement of the inertia member for advancing the inertia member with relation to the projectile, a detonator with means for firing the detonator to i ite the time train when the inertia mem er is advanced, retainers for normally holding the inertia member, a longitudinally movable locking member cooperating with the retainers, and operating by reason of its inertia to release the retainers during the acceleration period of the projectile whereby the inertia member is freed to advance under the influence of its actuating spring.

5. A fuse for projectiles embodying a time train, an inertia member movable rearwardly longitudinally of the projectile, a normally expanded coil spring in the rear of the inertia member for advancing the same, a detonator and means for firing the same to ignite the time train when the inertia member is advanced, and deformable retainers and cooperating means for normally holding the inertia member partly retracted whereby during the acceleration period of the pro] ectile the inertia member will assume a rear position and power will be stored in the spring for advancing the inertia member to fire the detonator.

EMIL GATHMMANN. 

